Brake



Feb. 27, 1940. BURGER 2,192,004

BRAKE Filed Nov. 25, 1938 /5 ,I if

ATTORNEY.

2 Sheets-Sheet 1 Feb. 27, 1940. w. BURGER 2,192,004

BRAKE Filed Nov. 25, 1938, 2 Sheets-Sheet 2 INVEN TOR. FPmiF/awMidi-45F! ATTORNEY;

Patented Feb. 27, 1949 PATENT oFFicE BRAKE FrederickWLBurger, Niles,Mich, assignor to Clark Equipment Company, Buchanan, Mich., acorporation of Michigan Application November. 25, 1938, Serial No.242,168

11 Claims.

This invention relates to brakes, and more particularly is directed to abrake actuating mechanism of the mechanical type to be used inconjunction with the conventional type of hy- 5 draulic brake assembly.

It is essential, in connection with the usual hydraulic brake assemblyused for service braking, to provide some mechanical means of expandingthe brake shoes against the drum, since: the hy- 10 draulic brakeactuator is not useable asa parking or emergency brake. Such mechanicalmeans have taken various forms in assemblies with which I am familiar,but one of the common defects of most of such constructions isthe'inadel5 quate support provided on the backing plate for holding thearms or links through which the braking force is applied againstbuckling or misalinement.

Still another disadvantage of previous types 2 of such mechanisms hasbeen the difliculty of finding suificient space in the conventionalassembly to locate supports and guides for the arms, these supports andguides being customarily secured to the backing plate.

25 The present invention has for one of its primary objectsthe-provision of a mechanical brake actuating mechanism which has rigidguiding support for the movement of the pressure-applying arms, andwhich prevents any possibility of 30 these arms buckling or binding inservice.

Another object of the present invention is the provision of a supportingstructure for the actuating mechanism which is independent of thebacking plate, andis supported directly by the 35 hydraulic cylinder.This eliminates welding, riveting or otherwise securing guide andsupport members to the backing plate, and eliminates any changes in thecontour or shape of the plate, requiring only a slot for receiving theprojecting 40 end of the actuating lever.

Still another advantage secured bythe present invention is a design ofthis mechanism such that the basic parts may be made from sheet metalstampings, and may be readily assembled with conventional screws andbolts. This provides asimplified economical construction: that can bebuilt at low cost. I

Other objects and advantages'of the'present invention will be moreapparent fromthe follow- 50 ing detailed description which, taken inconjunction with the accompanying drawings, will disclose to thoseskilled in the art the particular construction and operation of apreferred form of the present invention. i

55 .In thedrawings:

Figure 1 is an elevational view of a brake assembly embodying thepresent invention;

Figure 2 is a sectional View thereof taken on line 22 of Figure 1;

Figure 3 is a plan view of the mechanical brake actuating structure;

Figure 4 is a detailed elevational view showing the brake inengagedposition; and

Figure 5 is a view similar to Figure 4 of a modifled form of theinvention.

Referring now in detail to the drawings, I have disclosed a brake plate5 having a central offset portion 6 providing an aperture 1 adapted tofit over an axle housing arm and having the circumferential series ofopenings 8 for receiving '15 the rivets by which the plate may besecured to the brake flange on the housing. The plate 5 is also providedwith a peripheral flange portion 9 adapted to embrace the brake drumcarriedby the wheel and to enclose the lateral edge thereof.

Pivotally mounted on the plate 5 are a pair of brake shoes I0 which atone end are anchored to the plate by means of the studs I2, these studshaving eccentric bearing portions [3 and projecting through the plateand secured thereto by the nuts l4. Rotation of the studs l3 by means ofa suitable wrench engaging the slabbed-ofi end I5 of the studs willproduce proper adjustment of the position of the pivoted end of thebrake shoes [0. At their opposite end the shoes l0 are provided withsemi-circular transverse recesses [6 adapted to receive the ends ll ofpiston rods l8 carried Within the hydraulic cylinder !9 which is securedin an opening in the brake flange by means of the cap screws 20. Thecylinder I9, as shown more clearly in Figure 2, is provided with aninlet opening 22having a connection 23 for the hydraulic conduit bywhich fluid under pressure is admitted to the interior of the cylinderto spread apart the pistons carried at the inner ends of the arms: l8.

Below the recesses HS in the brake shoes, each of the shoes is providedwith a boss portion 24 having slots 25 therein providing anchor supportsfor the ends of a contracting spring 26 which normally tends to contractthe shoes to brake releasing position. Suitable cams 21 are anchored onthe backing plate 5 and are provided with stud portions 28 extendingthrough the backing plate for adjustment of the position of the shoesrelative to the drum.

The cylinder I9 is provided with two depending boss portions 30 whichare suitably tapped to receive the countersunk screws 32, these screwsbeing adapted to support an L-shaped plate 33 notched end portionsadapted to engage rthe. bosses 24 of the brake shoes 58. At their innerends the arms 36 are provided with cam portions 31 which are adaptedtoengage in suitable corresponding cam surfaces 38 formed in.anactuating lever 39 extending transversely through the slot fill in thebacking plate 5 and throughcorresponding slots 52 and ll? in the members33 and34, respectively. This actuating leveiwat its outer end is adaptedto carry a clevis a l to which is securedthe cable '45 or similaractuating mechanism leading to a hand brake lever or the like. The lever39 is adapted to be mounted for rotation about a pivot pin Ell, carriedthereby, which pin is guided within longitudinal slots 52formed in theupper and lower surfaces of the guide comprising the members 33 and 31.This: allows for floating movement of the pivot to produce an equalizingbrake applying pressure on each of the arms 35 upon rotation of thelever 3%. The arms 3d are mounted for movement on suitable pins 53carrying guide sleeves 5d thereon and extending through slots 55 formedin the arms. This allows slight cocking of the arms Within the guideduring actuation thereof, but retains the arms against displacement outof the guides and prevents rattling of the arms therein. The pins 53preferably comprise bolts which are securedbetween the upper and lowerportions of the members 33 and 36 to hold these two L-sha'ped memberstogether, and the sleeves mounted on the pin 53 serve as spacing membersfor preventing any binding of the arms 36 within the guide.

It will thus be apparent that the entire brake actuating mechanism,including the actuating lever 39, the two arms 36 and the guide 3334 aresuspended from the hydraulic cylinder l9 by means of the screws 32, andare entirely independent of any other support on the backing plate. Thisprovides a very desired type of construction since it eliminates thenecessity of spot Welding or otherwise securing guides or supports tothe backing plate, and also insures that the mechanism can be supportedin the structure regardless of the particular shape or configuration ofthe backing plate. In addition, the hydraulic cylinders can be formedwith the boss portions 30 "regardless of whether or not the mechanicalbrake mechanism is to be applied, thus making them adapted for use withor without such a mechanical brake applying system. Preferably, asuitable sealing leather or gasket 68 is carried on the lever 39intermediate the flange of the members? and the slot in the backingplate 5. This leather closely fits about the lever 39 and insures thatthe slot '40 will be sealed against the entrance of dirt or moisture inthe use of the brake mechanism. The leather E55} moves longitudinallyupon rotation of the lever 38, thus at all times closing the slot 453about the lever.

In Figure 4 the mechanism is shown in brake expanded position whereinthe hydraulic brake has been operated to expand the shoes in which eventthe mechanical brake system 'remainssin hydraulic .brake application,

shaped brackets 62 spot welded or otherwise f inoperative position, theboss portions 24' of the shoes moving slightly outwardly with respect tothe notches in the ends of the arms 36. It is apparent that either ofthe braking systems can be operated to expand the shoes independently 5of the other, and that the mechanical brake applying means in no'wayinterferes with the The. dotted linev position of the arm 39, ,as shownin Figure 3,

illustrates the possible amount of take-up which 10 -.-may be had in themechanical brake system as a the lining of the brake shoes Wears.Actually,

the rotation of the arm 39 for any particular brakeapplication is only afew degrees, butas the brake, lining wears,the arm is progressively 15.movearrom the full line position to the dotted line position of Figure3 to accommodate this wear. V

.The useof the slots 55 is necessary in order to allow the arms tofollow in engagement with the b'ossesg2 l' upon: the -m0vement of thelever 39, since the cam portions 38 and 31 will produce aslight cookingof the arms in the rotation of. the lever 39. Y

In Figure 5 I have shown a modified form of 5 construction in whichthehydraulic cylinder 19 is not provided with the boss portions 30 forsupporting the mechanical brake mechanism, but this mechanism issupported by means of L- secured to thebacking plate 5 and havingnormally extending flange portions engaged under 7 the nuts 63 of thepins53. This serves to support the mechanism in substantially the samemanner as previously described inasmuch as the 5135 members 33. ,an'd34are thereby held in proper positionfor supporting the'arms 36 and theactuating lever 39 which projects outwardly through the backing plateand has its inner end moving inthe slotted out portion 43 of the member34.114 0 This is merely a modification of, the support on the hydrauliccylinder for use in cases where aparticular cylinder is employed thatdoes not have the tapped bosses 38 to adapt the present actuatingmechanism to structures now in uses-15 The operation of the mechanismshown in Figure-5, insofar as brake applying and releasing is concerned,is identical with that previously described, and it is therefore notbelieved necessary to give a detailed description thereof.

It. will be apparent that all of theparts of themechanism maybe formedof metal stampings or .the like, which render them very eco-, nomical-inmass production and also-facilitate the assembly of the parts at lowcost. Further, s

the design is simple and may be adjusted for -wear without anydifiiculty.

I-am aware that slight changes may be made 'in .certain' details of thepresent construction without, however, departing from the underlying 0principles thereof, and I therefore do not intend to be limited exceptas defined by the scope and spirit of the appended claims.

I claim:

1. In combination, a hydraulic brake actuating r 5 cylinder, a pair ofangle plates arranged to form a box-section support extendinglongitudinally beneath said cylinder, means securing said plates againstrelative movement, brake-shoe-engaging arms reciprocably mounted in saidsupport, and

-means'for securing the upper plate of said supportto said cylinder.

2.. In combination, a hydraulic brake actuating cylinder, a pair ofbrake shoe engaging arms, a-

support enclosing the major portion'of said arms gitudinal movement.

extending longitudinally beneath said cylinder, and means securing saidsupport to said cylinder.

3. In combination, a backing plate, a pair of brake shoes pivotallymounted thereon, a boxsection open-ended guide secured intermediate saidshoes, a pair of oppositely extending arms guided for reciprocablemovement therein and adapted to have limited transverse rockingmovement, an actuating lever extending laterally into said guide andpivoted intermediate the ends of the arms, said lever having camportions engaging said arm ends for moving the arms in oppositedirections and transversely rocking the same upon rotation of the leverto move said shoes apart, and spring means normally tending to contractsaid shoes.

4. A brake assembly comprising a backing plate, a pair of brake shoespivotally mounted thereon, a hydraulic cylinder mounted on said plateintermediate said shoes, a pair of coplanar arms engaging said shoes andhaving their adjacent ends formed with diagonal cam surfaces, anactuating lever for spreading said arms apart pivoted intermediate saidarm ends and having cooperating cam surfaces terminating in stopportionsfor limiting rotation of said lever, and means for guiding andsupporting said arms and lever secured to said cylinder.

5. A brake assembly comprising a backing plate, a pair of brake shoespivotally mounted thereon, and mechanical brake actuating meanscomprising a pair of oppositely extending arms engaging said' shoes, alever pivotally mounted intermediate said arms and having cammingengagement with the adjacent ends thereof, and a box-like housingsupporting said lever and arms and having means providing limitedlateral rocking of said arms and guiding said arms for lon- 6. Incombination, a mechanical brake actuating mechanism for a conventionalhydraulic brake assembly including a pair of pivotally mounted brakeshoes, comprising a pair of L-shaped plates arranged to form arectangular-section, hollow guide means intermediate said shoes, an armextending from each end thereof engageable with the adjacent shoe, alever projecting laterally of said guide means and having pivotalsupport thereon, and interengaging cam means on the lever and theadjacent ends of said arms whereby rotation of said lever tends to movesaid arms outwardly of said guide means, said cam means including stopmeans limiting rotation of said lever in brake applying direction. a

7. In combination, a mechanical brake actuating mechanism for aconventional hydraulic brake assembly including a pair of pivotallymounted brake shoes, comprising hollow guide means intermediate saidshoes, an arm extending from each end thereof engageable with theadjacent shoe means in said guide means preventing binding of said armstherein, a lever projecting laterally of said guide means and havingpivotal support thereon, and interengaging cam means on the lever andthe adjacent ends of said arms whereby rotation of said lever tends tomove said arms outwardly of said guide means.

8 In combination with a hydraulic brake assembly including a pair ofbrake shoes and an actuating cylinder, a mechanical brake applyingmechanism comprising a housing extending between said shoes and ofrectangular section, a pair of arms having opposite ends engaging saidshoes, means intermediate the ends of said arms limiting their movementrelative to said housing, an actuating lever extending laterally intosaid housing between the adjacent ends of said arms and having cam meansfor moving said adjacent ends of said arms apart upon rotation of saidlever.

9. The combination of claim 8 wherein the opposite side walls of saidhousing are cut away to accommodate movement of said lever.

10. The combination of claim 8 wherein said housing comprises twoopposite arranged L- shaped plates, and means for securing the upperplate to the bottom of said cylinder.

11. A brake assembly comprising a backing plate, a pair of brake shoespivotally mounted thereon, a housing extending transversely betweensaidshoes and fixed relative to said plate, a pair of arms extendingoutwardly from opposite ends of said housing and engaging said shoes, adiagonal slot in each armintermediate the ends thereof, pin meansadjacent each end of said housing engaging in said slots for limitingmovement of said arms, an actuating member pivoted in said housingintermediate said arms, and cam means on said member engaging adjacentarm ends.

FREDERICK W. BURGER.

